Line breaking and floating

Question

I have a matrix and I want to show some lines of text floating right to the matrix. The problem is that the following code shows two lines of text without executing \\ break-line.

\[ M = \left( \begin{array}{cccc}
a & b & c & d \\
1 & 2 & 3 & 4\\
a & b & c & d\\
1 & 2 & 3 & 4 \end{array} \right)\ Something  \\ Something
] 

How can I fix it?

Answer 1

Depending on what it is you want to write next to the matrix, you can always stack it in a tabular:

\documentclass{article}
\begin{document}
\[
  M = \left( \begin{array}{cccc}
    a & b & c & d \\
    1 & 2 & 3 & 4\\
    a & b & c & d\\
    1 & 2 & 3 & 4
  \end{array} \right) \qquad
  \begin{tabular}{@{}l}
    First row \\ Row number 2 \\ Third row \\ Last or fourth row.
  \end{tabular}
\]
\end{document}

Creating matrices is also somewhat automated using other constructions. See Where is the \matrix command? For example, your matrix could be created using a pmatrix environment.